SUMMARYUnder suitable conditions, the region of the aqueous phase immediately adjacent to a glass‐water interface can be selectively illuminated using the evanescent wave created when total internal reflection occurs at the interface. Objects in the aqueous phase away from the glass become effectively invisible, since the intensity of the evanescent wave decays exponentially with distance from the interface. Previous methods of generating evanescent waves for light microscopy have employed accessory light sources and optical components that directed the illumination on the specimen from one side. The asymmetric illumination creates a surprising orientation dependence of visibility for some specimens. Objects such as microtubules are totally invisible unless they are orientated nearly perpendicular to the direction of illumination. An explanation of this phenomenon is provided in terms of the geometry of diffraction of light by long thin objects.A simple method of achieving evanescent‐wave illumination is described and shown to be useful in practice for biological specimens. In contrast to previously described methods, the present arrangement has the advantage of producing circularly symmetric illumination, and of utilizing only standard optical microscope components. The system has been used for imaging specimens both by light scattering and by fluorescence. It has proved useful for following the fragmentation of flagella into isolated microtubules, observing microtubules gliding over dynein adsorbed to a surface, and also for determining the arrangement of vinculin and alpha‐actinin in cell‐substratum attachment sites and termini of growing myofibrils in cardiac cells.

Murray, J. M., & Eshel, D. (1992). Evanescent‐wave microscopy: A simple optical configuration. Journal of Microscopy, 167(1), 49–62. Portico.